Microresonators are microfabricated resonating elements having numerous applications, including signal processing and sensing. For example, microresonators fabricated from aluminum nitride (AlN) are used in radiofrequency (RF) filters, accelerometers, and sensors. AlN is one example of a piezoelectric material that responds both electrically and mechanically to applied electric signals, and that can be formed into an electroacoustic resonator capable of modifying such signals.
For any MEMS-based filter, signal degradation can arise from undesired spurious responses. For instance, an AlN microresonator can efficiently transduce numerous symmetric and anti-symmetric Lamb modes, but spurious modes can arise from acoustic waves interacting with various device components. Accordingly, additional resonator architectures and methods are needed to reduce and mitigate such spurious responses.